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thomas_2002 wrote:

bernard wrote:

thomas_2002 wrote:im getting ready to build the pulley launcher and was wondering if i should use three pulleys or two?

Where do you want to put each pulley?

basically one in the back of the "cube" and one of the top part of the front part and then one below that.

Too understand what you want to do I'll need more specific descriptions perhaps also diagrams. What purpose do you want each of the pulleys to serve? In one setup three pulleys could be essential while it could be excessive in another.

bernard wrote:

thomas_2002 wrote:

bernard wrote: Where do you want to put each pulley?

basically one in the back of the "cube" and one of the top part of the front part and then one below that.

Too understand what you want to do I'll need more specific descriptions perhaps also diagrams. What purpose do you want each of the pulleys to serve? In one setup three pulleys could be essential while it could be excessive in another.

this is basically what design I want sorry for the horrible drawing

thomas_2002 wrote:

bernard wrote:

thomas_2002 wrote:
basically one in the back of the "cube" and one of the top part of the front part and then one below that.

Too understand what you want to do I'll need more specific descriptions perhaps also diagrams. What purpose do you want each of the pulleys to serve? In one setup three pulleys could be essential while it could be excessive in another.

good.png

this is basically what design I want sorry for the horrible drawing

I think I understand what you mean--and I think you could save a pulley if you eliminated the pulley at the top right in your diagram, and then your rope/string that pulls the ETV will be at a diagonal.

bernard wrote:

thomas_2002 wrote:

bernard wrote: Too understand what you want to do I'll need more specific descriptions perhaps also diagrams. What purpose do you want each of the pulleys to serve? In one setup three pulleys could be essential while it could be excessive in another.

good.png

this is basically what design I want sorry for the horrible drawing

I think I understand what you mean--and I think you could save a pulley if you eliminated the pulley at the top right in your diagram, and then your rope/string that pulls the ETV will be at a diagonal.

Would the diagonal help it go farther or anyway?

Side Question:
Would adding another pulley to my launcher be effective, or would it just slow my ETV down?

THX SO MUCH BERNARD
but i havent started the launcher yet still, and my events in 3 - 4 wks
im screwed ik
so do u think i should just make a pulley launcher or continue to use the spring launcher like planned?

Eggo wrote:Side Question:
Would adding another pulley to my launcher be effective, or would it just slow my ETV down?

Well, adding another pulley does add more friction because you now have your string going through and rubbing yet another surface. The least amount of pulleys is the best choice.

Shanta wrote:THX SO MUCH BERNARD
but i havent started the launcher yet still, and my events in 3 - 4 wks
im screwed ik
so do u think i should just make a pulley launcher or continue to use the spring launcher like planned?

Pulley launcher design not to far from a spring launcher. Spring launcher can be difficult to get working in 3-4 weeks, it could be possible, but have a design ready in case it doesn't work--that would be the pulley launcher.

bernard do you mean i should make 2???
or should i just go with the pulley
is spring that much better than pulley?

Shanta wrote:bernard do you mean i should make 2???
or should i just go with the pulley
is spring that much better than pulley?

No, you only need to make one. A spring launcher typically will be able to get you much faster times than a pulley launcher. But getting a spring launcher to work can be tricky, especially in the limited time you have. Since a spring launcher is not too different from a pulley launcher, my recommendation is to start with a pulley launcher but design it os that it is not difficult to convert into a spring launcher. Notice that for my device, if I remove the elastic band and do not use the bow release, it acts as a pulley launcher.